U.S. patent number 10,987,667 [Application Number 16/302,303] was granted by the patent office on 2021-04-27 for flow control system for diagnostic assay system.
This patent grant is currently assigned to Integrated Nano-Technologies, Inc.. The grantee listed for this patent is Integrated Nano-Technologies, Inc.. Invention is credited to Dennis M. Connolly, Richard S. Murante, Mark J. Smith, Nathaniel E. Wescott.
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United States Patent |
10,987,667 |
Wescott , et al. |
April 27, 2021 |
Flow control system for diagnostic assay system
Abstract
A disposable cartridge for mitigating cross-contamination of
fluid sample reagents. The disposable cartridge includes a
cartridge body defining a syringe barrel having an barrel port
operative to inject and withdraw assay fluids in response to the
displacement of a syringe plunger. Furthermore, the disposable
cartridge includes a rotor defining a plurality of assay chambers
in fluid communication with the barrel port through one of a
plurality of rotor ports disposed about the periphery of the rotor.
Finally, the disposable cartridge includes a flow control system
between the barrel and rotor ports which prevents
cross-contamination of fluid sample reagents from one assay chamber
to another assay chamber.
Inventors: |
Wescott; Nathaniel E. (West
Henrietta, NY), Connolly; Dennis M. (Rochester, NY),
Murante; Richard S. (Rochester, NY), Smith; Mark J.
(Rochester, NY) |
Applicant: |
Name |
City |
State |
Country |
Type |
Integrated Nano-Technologies, Inc. |
Henrietta |
NY |
US |
|
|
Assignee: |
Integrated Nano-Technologies,
Inc. (Henrietta, NY)
|
Family
ID: |
1000005513264 |
Appl.
No.: |
16/302,303 |
Filed: |
May 16, 2017 |
PCT
Filed: |
May 16, 2017 |
PCT No.: |
PCT/US2017/032904 |
371(c)(1),(2),(4) Date: |
November 16, 2018 |
PCT
Pub. No.: |
WO2017/201049 |
PCT
Pub. Date: |
November 23, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190293673 A1 |
Sep 26, 2019 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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62337446 |
May 17, 2016 |
|
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62337423 |
May 17, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N
1/4077 (20130101); G01N 35/1095 (20130101); B01L
3/502746 (20130101); B01L 3/502 (20130101); B01L
2200/04 (20130101); B01L 2300/0681 (20130101); G01N
2001/4088 (20130101); B01L 2300/042 (20130101); B01L
2200/0631 (20130101); B01L 2200/028 (20130101); B01L
2400/0487 (20130101); B01L 2400/0633 (20130101) |
Current International
Class: |
B01L
3/00 (20060101); G01N 35/10 (20060101); G01N
1/40 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
PCT/US2017/032904, filed May 16, 2017; International Search Report
dated Aug. 8, 2017, Integrated Nano-Technologies, Inc. (9 pages).
cited by applicant.
|
Primary Examiner: Wecker; Jennifer
Assistant Examiner: Bortoli; Jonathan
Attorney, Agent or Firm: Barclay Damon LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a Non-Provisional Utility Patent application
which claims priority from a first U.S. Provisional Patent
Application Ser. No. 62/337,423 filed May 17, 2016 entitled
"Modified Desalting Column" and a second U.S. Provisional Patent
Application Ser. No. 62/337,446 filed May 17, 2016 entitled
"Multi-Chamber Rotating Valve and Cartridge" The contents of the
aforementioned applications are hereby incorporated by reference in
their entirety.
This application also relates to U.S. patent application Ser. No.
15/157,584 filed May 18, 2016 entitled "Method and System for
Sample Preparation" which is a continuation of U.S. Non-Provisional
patent application Ser. No. 14/056,603, filed Oct. 17, 2013, now
U.S. Pat. No. 9,347,086, which claims priority to U.S. Provisional
Patent Application Ser. No. 61/715,003, filed Oct. 17, 2012, which
is a continuation-in-part of U.S. patent application Ser. No.
12/785,864, filed May 24, 2010, now U.S. Pat. No. 8,663,918, which
claims priority to U.S. Provisional Patent Application Ser. No.
61/180,494, filed May 22, 2009, and which is also a
continuation-in-part of U.S. patent application Ser. No.
12/754,205, filed Apr. 5, 2010, now U.S. Pat. No. 8,716,006, which
claims priority to U.S. Provisional Patent Application Ser. No.
61/166,519, filed Apr. 3, 2009. The contents of the aforementioned
applications are hereby incorporated by reference in their
entirety.
Claims
What is claimed is:
1. A disposable cartridge for use in combination with a diagnostic
assay system, comprising: a cartridge body defining a syringe
barrel having a barrel port operative to inject and withdraw assay
fluids in response to the displacement of a syringe plunger; a
rotor comprising a plurality of assay chambers rotatable about an
axis and mounted for rotation to the cartridge body, the rotor
defining a plurality of ports disposed about a peripheral surface,
each port disposed in fluid communication with at least one of the
assay chambers; a compliant over-mold interposed between the
cartridge body and the rotor and defining at least one compliant
opening corresponding to interposing the barrel port and one of the
rotor ports.
2. The disposable cartridge of claim 1 wherein the compliant
opening includes an aperture having a dimension smaller than the
dimension of the barrel port.
3. The disposable cartridge of claim 1 wherein the compliant
opening includes an aperture having a dimension smaller than the
dimension of the barrel port and the dimension of each of the rotor
ports and wherein the compliant opening is configured to enlarge
when fluid pressure is applied and diminish when fluid pressure is
reduced.
4. The disposable cartridge of claim 2 wherein the compliant
opening includes a flap configured to cover the opening.
5. The disposable cartridge of claim 2 wherein the compliant
opening includes intersecting cuts disposed through the
over-mold.
6. The disposable cartridge of claim 2 wherein the compliant
opening includes intersecting cuts disposed through the over-mold,
wherein the intersecting cuts define a cross-over region and
wherein a portion of the cross-over region is removed to facilitate
fluid flow through the cross-over region.
7. The disposable cartridge of claim 4 wherein the flap includes an
elastomer hinge configured to open and close the flap over the
opening.
8. The disposable cartridge of claim 6 wherein the portion of the
cross-over region is less than about 0.5 mm.
9. The disposable cartridge of claim 6 wherein the portion of the
cross-over region is less than about 0.3 mm.
10. A disposable cartridge for use in combination with a diagnostic
assay system, comprising: a cartridge body defining a syringe
barrel having a barrel port operative to inject and withdraw assay
fluids in response to the displacement of a syringe plunger; a
rotor comprising a plurality of assay chambers rotatable about an
axis and mounted for rotation to the cartridge body, the rotor
defining a plurality of ports disposed about a peripheral surface,
each port disposed in fluid communication with at least one of the
assay chambers; a flow control system between the barrel and rotor
ports preventing cross-contamination of fluid sample reagents from
one assay chamber to another assay chamber.
11. The disposable cartridge of claim 10 wherein at least two ports
of the flow control system which transfer compatible reagents are
disposed in a common plane normal to the axis.
12. The disposable cartridge of claim 10 wherein at least two ports
of the flow control system which transfer incompatible reagents are
disposed in different planes normal to the axis.
13. The disposable cartridge of claim 12 wherein ports of the flow
control system associated with one plane are spaced-apart from the
ports of another plane by a prescribed vertical distance.
14. The disposable cartridge of claim 10 wherein at least one of
the rotor ports include a high viscosity gel disposed in a bore of
the port, the high viscosity gel containing the fluid sample
reagents in their respective chambers prior to use.
15. The disposable cartridge of claim 10 wherein at least one of
the rotor ports include a high viscosity gel disposed in a bore of
the port, the high viscosity gel being displaced under pressure to
enable the transfer of fluid sample reagents from one assay chamber
to another assay chamber.
16. The disposable cartridge of claim 10 wherein at least one of
the rotor ports define a fluid volume which is less than about 15
microliters to prevent back-flow of a fluid sample reagent.
17. The disposable cartridge of claim 10 wherein the flow control
system includes an elastomer over-mold interposing the cartridge
body and at least a portion of the peripheral surface of the rotor,
the elastomer over-mold having at least one compliant opening
corresponding to the barrel port.
18. A disposable cartridge for use in combination with a diagnostic
assay system, comprising: a cartridge body defining a syringe
barrel having a barrel port operative to inject and withdraw assay
fluids in response to the displacement of a syringe plunger; a
rotor comprising a plurality of assay chambers rotatable about an
axis, the rotor defining a plurality of ports disposed about a
peripheral surface, each port disposed in fluid communication with
at least one of the assay chambers; a flow control system between
the barrel and rotor ports preventing cross-contamination of fluid
sample reagents from one assay chamber to another assay chamber; at
least one of the ports of the flow control system including a high
viscosity gel disposed in at least one of the rotor ports to
contain fluid sample reagents in their respective chambers.
19. The disposable cartridge of claim 18 wherein the high viscosity
gel is displaced under pressure to enable the transfer of fluid
sample reagents from one assay chamber to another assay
chamber.
20. The disposable cartridge of claim 18 wherein the high viscosity
gel is chemically inert with respect to the fluid sample reagents.
Description
TECHNICAL FIELD
This invention relates to a disposable cartridge for use in
combination with a diagnostic assay system which performs RNA
polymerase-DNA analysis of a biological sample. The assay system
drives a rotor about a rotational axis as a syringe plunger injects
and withdraws sample fluids into and out of the disposable
cartridge. Embodiments of a disposable cartridge are disclosed
including variations which facilitate flow, repeatability,
reliability, admixture, and preparation of the assay fluids.
BACKGROUND
There is continuing interest to improve testing methodologies,
facilitate collection and decrease the time associated with
clinical laboratories. Particular testing requires that a sample be
disrupted to extract nucleic acid molecules such as DNA or RNA.
The number of diagnostic tests performed annually has increased
exponentially in the past decade. The use of molecular diagnostics
and gene sequencing in research and medical diagnostics is also
rapidly growing. For example, DNA testing has also exploded in view
of the growing interest in establishing and tracking the medical
history and/or ancestry of a family. Many, if not all of these
assays, could benefit from a rapid sample preparation process that
is easy to use, requires no operator intervention, is cost
effective and is sensitive to a small sample size.
Sample collection and preparation is a major cost component of
conducting real-time Polymerase Chain Reaction (PCR), gene
sequencing and hybridization testing. In addition to cost, delays
can lead to the spread of infectious diseases, where time is a
critical component to its containment/abatement. In addition to
delaying the test results, such activities divert much-needed
skilled resources from the laboratory to the lower-skilled
activities associated with proper collection, storage and
delivery.
For example, a portable molecular diagnostic system could be
operated by minimally trained personnel (such as described in US
2014/0099646 A1) and have value with regard to disease
surveillance. However, the adoption of such portable systems can be
limited/constrained by current methods of sample collection, which
require trained personnel to permit safe and effective handling of
blood/food/biological samples for analysis. Other limitations
relate to: (i) the ability of injected/withdrawn fluids to properly
flow, (ii) manufacturability, (iii) cross-contamination of assay
fluids which may influence the veracity of test results, (iv)
proper admixture of assay fluids to produce reliable test results,
and (v) the ability or inability to introduce catalysts to speed
the time of reaction,
A need, therefore, exists for an improved disposable cartridge for
use in combination with a portable molecular diagnostic/assay
system which facilitates/enables the use of minimally-trained
personnel, hands-off operation (once initiated),
repeatable/reliable test results across multiple assay samples
(e.g., blood, food, other biological samples) and an ability to
cost effectively manufacture the disposable cartridge for the
diagnostic assay system.
SUMMARY
The present disclosure relates to a variety of disposable cartridge
configurations for a portable molecular diagnostic/assay
system.
In one embodiment, a filtration column assembly is provided for use
in combination with a disposable cartridge of a diagnostic assay
system. The filtration column assembly includes a column matrix
material configured to filter a fluid sample, a tubular column
configured to sealably engage a filtration chamber of the
disposable cartridge and a cap configured to be inserted into an
end of the tubular column and define a passageway to direct the
sample fluid from the second end of the tubular column into a
collection cavity disposed adjacent the filtration chamber. The
tubular column defines: (i) a column cavity for receiving the
column matrix material, (ii) a first end having an opening for
receiving the fluid sample and configured to retain the column
matrix material, and (iii) a second end, receiving the fluid
directing cap, and having an opening to dispense a filtered fluid
sample from the column cavity.
In another embodiment, a disposable cartridge is provided for
mitigating cross-contamination of fluid sample reagents. This
embodiment includes a cartridge body defining a syringe barrel
having an barrel port operative to inject and withdraw assay fluids
in response to the displacement of a syringe plunger. Furthermore,
the disposable cartridge includes a rotor defining a plurality of
assay chambers disposed in fluid communication with the barrel port
through one of a plurality of rotor ports disposed about the
periphery of the rotor. Finally, the disposable cartridge includes
a flow control system between the barrel and rotor ports which
prevents cross-contamination of fluid sample reagents from one
assay chamber to another assay chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is disclosed with reference to the
accompanying drawings, wherein:
FIG. 1 is a perspective view of a portable diagnostic assay system
operative to accept one of a plurality of disposable cartridges
configured to test fluid samples of collected blood/food/biological
samples.
FIG. 2 is an exploded perspective view of one of the disposable
cartridges configured to test a blood/food/biological sample.
FIG. 3 is a top view of the one of the disposable cartridges
illustrating a variety of assay chambers including a central assay
chamber, one of which contains an assay chemical suitable to
breakdown the fluid sample to detect a particular attribute of the
tested fluid sample.
FIG. 4 is a bottom view of the disposable cartridge shown in FIG. 3
illustrating a variety of channels operative to move at least a
portion of the fluid sample from one chamber to another the purpose
of performing multiple operations on the fluid sample.
FIG. 5 is an exploded perspective view of the disposable cartridge
including a filtration column assembly comprising a column matrix
material, a tubular column receiving and retaining the column
matrix material, and a fluid directing cap configured to restrict
the volume of a filtered fluid sample while maintaining a
pressurized flow path.
FIG. 6 is a cross-sectional view taken substantially along line 6-6
of FIG. 5 wherein a plurality of ports are depicted in a common
plane of the cartridge rotor.
FIG. 7 is a cross-sectional view taken substantially along line 7-7
of FIG. 6 depicting the filtration column disposed in a filtration
chamber of the disposable assay cartridge.
FIG. 8 is an isolated perspective view of the filtration column
depicting a fluid guide operative to direct the filtered fluid
sample into a collection chamber.
FIG. 9 is an exploded perspective view of the filtration column
including the column matrix material, the tubular column for
receiving the column matrix material, the fluid directing cap and a
retention filter melted, welded, or otherwise attached to the lower
end of the tubular column.
FIG. 10 is an exploded, isolated, perspective view of the fluid
directing cap depicting the underside surface of the cap, including
a retention filter disposed in combination with an annular rim of
the fluid directing cap.
FIG. 11 is a schematic side sectional view of the filtration column
including the column matrix material for trapping/filtering small
molecule materials while allowing the passage of large
molecules.
FIG. 12 is a cross-sectional view taken substantially along line
12-12 of FIG. 5 wherein a plurality of rotor ports are depicted in
a common plane along with the syringe barrel and a barrel port of
the cartridge body.
FIG. 13 depicts an exploded perspective view of the disposable
cartridge assembly including a compliant over-mold disposed between
the rotor and the cartridge body.
FIG. 14 is a cross-sectional view of the disposable cartridge taken
substantially along line 14-14 of FIG. 12 depicting an internal
view of the compliant over-mold to show the location of several
compliant openings in the over-mold.
FIG. 15 is a cross-sectional view of the disposable cartridge taken
substantially along line 15-15 of FIG. 14 depicting an X-shaped
valve disposed in a compliant over-mold for preventing backflow
contamination from one assay chamber to another.
FIG. 16 is an enlarged plan view of the X-shaped valve depicting
the size differential between the opening of the X-shaped valve and
the diameter of the barrel port of the cartridge body.
FIG. 17 is a cross-sectional view of the disposable cartridge taken
substantially along line 17-17 of FIG. 12 depicting an internal
view of the compliant over-mold to show the location of several
compliant openings in the over-mold.
FIG. 18 is a cross-sectional view of the disposable cartridge taken
substantially along line 18-18 of FIG. 17 depicting a flap valve
disposed in the compliant over-mold for preventing backflow
contamination from one assay chamber to another assay chamber.
FIG. 19 is an enlarged plan view of the flap valve depicting the
size differential between the opening of the flap valve and the
diameter of the barrel port of the cartridge body.
FIG. 20 is a sectional view through the disposable cartridge
depicting a vortex generator disposed downstream of a rotor port to
facilitate mixture of the assay fluids within the respective
chamber of the rotor.
FIG. 21 is an enlarged, broken-away side view of the vortex
generator shown in FIG. 20.
FIG. 22 is an bottom view of the rotor depicting an enlarged
channel which may be heated to accelerate reagent reactions within
the channel.
FIG. 23 depicts a bottom view of the rotor depicting segmented
channels for performing various PCR reactions therein.
FIG. 24 depicts a series of primer interactions including the steps
of: (i) resuspension of the primer by a buffer, (ii) purging the
buffer, (iii) sealing the rehydrated primers in the respective
suspension wells, and (iv) PCR product diffusion.
FIGS. 25a-25d are sectional views of the disposable cartridge
illustrating various alternative embodiments for preventing
cross-contamination from one disposable cartridge to another when
using a common diagnostic assay test device wherein FIG. 25a
depicts a disposable shaft, FIG. 25b depicts a series of compliant
washers disposed within the syringe barrel to limit exposure of a
permanent shaft of the diagnostic assay device to the assay fluids,
FIG. 25c shows a bellows diaphragm to fully contain the fluids
within the syringe barrel, and FIG. 25d illustrates a primary
working plunger disposed in combination with a secondary plunger
for preventing the permanent shaft from exposure to the
contaminating assay fluids.
Corresponding reference characters indicate corresponding parts
throughout the several views. The examples set out herein
illustrate several embodiments of the invention but should not be
construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION
A disposable cartridge is described for use in a portable/automated
assay system such as that described in commonly-owned, co-pending
U.S. patent application Ser. No. 15/157,584 filed May 18, 2016
entitled "Method and System for Sample Preparation" which is hereby
included by reference in its entirety. While the principal utility
for the disposable cartridge includes DNA testing, the disposable
cartridge may be used in be used to detect any of a variety of
diseases which may be found in either a blood, food or biological
specimen. For example, blood diagnostic cartridges may be dedicated
cartridges useful for detecting hepatitis, autoimmune deficiency
syndrome (AIDS/HIV), diabetes, leukemia, graves, lupus, multiple
myeloma, etc., just naming a small fraction of the various blood
borne diseases that the portable/automated assay system may be
configured to detect. Food diagnostic cartridges may be used to
detect Salmonella, E. coli, Staphylococcus aureus or dysentery.
Diagnostic cartridges may also be used to test samples from insects
and animals to detect diseases such as malaria, encephalitis and
the west nile virus, to name but a few.
More specifically, and referring to FIGS. 1 and 2, a portable assay
system 10 receives any one of a variety of disposable assay
cartridges 20, each selectively configured for detecting a
particular attribute of a fluid sample, each attribute potentially
providing a marker for a blood, food or biological (animal borne)
disease. The portable assay system 10 includes one or more linear
and rotary actuators operative to move fluids into, and out of,
various compartments or chambers of the disposable assay cartridge
20 for the purpose of identifying or detecting a fluid attribute.
More specifically, a signal processor 12, i.e., a PC board,
controls a rotary actuator (not shown) of the portable assay system
10 so as to align one of a variety of ports 18P, disposed about a
cylindrical rotor 18, with a syringe barrel 22B of a stationary
cartridge body 22. The processor 14 controls a linear actuator 24,
to displace a plunger shaft 26 so as to develop pressure i.e.,
positive or negative (vacuum) in the syringe barrel 22. That is,
the plunger shaft 26 displaces an elastomer plunger 28 within the
syringe 22 to move and or admix fluids contained in one or more of
the chambers 30, 32.
The disposable cartridge 20 provides an automated process for
preparing the fluid sample for analysis and/or performing the fluid
sample analysis. The sample preparation process allows for
disruption of cells, sizing of DNA and RNA, and
concentration/clean-up of the material for analysis. More
specifically, the sample preparation process of the instant
disclosure prepares fragments of DNA and RNA in a size range of
between about 100 and 10,000 base pairs. The chambers can be used
to deliver the reagents necessary for end-repair and kinase
treatment. Enzymes may be stored dry and rehydrated in the
disposable cartridge 20, or added to the disposable cartridge 20,
just prior to use. The implementation of a rotary actuator allows
for a single plunger 26, 28 to draw and dispense fluid samples
without the need for a complex system of valves to open and close
at various times. This greatly reduces potential for leaks and
failure of the device compared to conventional systems. Finally, it
will also be appreciated that the system greatly diminishes the
potential for human error.
In FIGS. 3 and 4, the cylindrical rotor 18 includes a central
chamber 30 and a plurality of assay chambers 32, 34 surrounded, and
separated by, one or more radial or circumferential walls. In the
described embodiment, the central chamber 30 receives the fluid
sample while the surrounding chambers 32, 34 contain a premeasured
assay chemical or reagent for the purpose of detecting an attribute
of the fluid sample. The chemical or reagents may be initially dry
and rehydrated immediately prior to conducting a test. Some of the
chambers 32, 34 may be open to allow the introduction of an assay
chemical while an assay procedure is underway or in-process. The
chambers 30, 32, 34 are disposed in fluid communication, i.e., from
one of the ports 18P to one of the chambers 30, 32, 34, by channels
40, 42 molded along a bottom panel 44, i.e., along underside
surface of the rotor 18. For example, a first port 18P,
corresponding to aperture 42, may be in fluid communication with
the central chamber 30, via aperture 50.
Filtration Cartridge
During development of the disposable cartridge, and as the
inventors acquired an appreciation for, and understanding of, the
fluid dynamics involved with respect to injecting, dispensing and
withdrawing the assay fluids, they discovered that surface tension
between components can significantly impact fluid flow from one
chamber 32 to another chamber 34. As a consequence, they learned
that the properties of surface tension can detrimental or
advantageous to fluid flow. For example, surface tension between a
film cover 60 (see FIG. 5), which encloses or encapsulates the
assay fluids of the various chambers 30, 32, 34, 36, and an upper
end of a filtration column assembly 100, can prevent the flow of
assay fluids from the filtration chamber 34 to an adjacent
collection chamber 36. The following discloses embodiments of a
filtration column assembly 100 which facilitates fluid flow from
the filtration chamber 34 to the collection chamber 36.
In FIG. 5, a novel filtration column assembly 100 comprises: (i) a
column matrix material 112 configured to filter a fluid sample;
(ii) a tubular column 114 having a column cavity for
receiving/retaining the column matrix material and configured to
sealably engage a filtration chamber 34 of the disposable cartridge
20, and (iii) a fluid directing cap 116, configured to be
detachably mounted to one end of the column and defining a
passageway (not viewable in FIG. 5) configured to direct a filtered
fluid sample from the tubular column 114 into the collection
chamber 36. In another embodiment of the novel filtration column
assembly 100, the cap 116 is configured to restrict the volume of
the filtered fluid sample collected above the column matrix
material 112 while maintaining a pressurized flow path.
In FIG. 6, a cross-sectional view through the key-hole shaped
filtration and collection chambers 34, 36 reveals a wall 38
separating the chambers 34, 38. FIG. 3 also depicts a separating
wall 38 which is about one-half (1/2) the wall height of the
filtration chamber 34. In the view shown, the filtration chamber 34
includes a plurality of raised surfaces or ridges 74 to facilitate
flow of the fluid sample from a port 74 through the cylindrical
wall 76 of the disposable cartridge 20, i.e., of the rotor 18. That
is, assay fluid will be injected into the port 74 which will, in
turn flow between the ridges 74, and into a bottom end of the
tubular column 114,
Inasmuch as the intervening wall 38, i.e., the wall separating the
filtration and collection chambers 34, 36, is less than the full
wall height of the filtration chamber 34, it will be appreciated
that, when fluid in the tubular column 114 reaches this level or
height, the sample fluid will accumulate in the filtration chamber
34 and flow over the wall 38 between the chambers 34, 36. To
prevent flow from taking this path or direction, i.e., over the
wall 38, without travelling through the length of the tubular
column 114, the bottom portion 124 of the tubular column 114 is
configured to sealably engage the surrounding filtration and
collection chamber walls 68. This forces pressurized assay fluid to
flow upward through the length of the tubular column 114.
The column matrix material 112 is a filter material which is
operative to secure, trap or chemically bond, a select material
suspended or flowing with, a carrier fluid, i.e., water, lysis
fluid, etc. In the illustrated embodiments, the column matrix
material 112 has transitioned from a dehydrated condition, i.e.,
shown in phantom in FIG. 9, to a hydrated condition, i.e., shown in
solid lines in FIGS. 5, 7, 9 and 11. Initially, the column matrix
material 112 is significantly smaller than the column cavity 122
and is retained therein by a screening material disposed at each
end of the tubular column 112. More specifically, a first filter
material 132 is melted, welded or otherwise affixed to the first
end of the tubular column 114 while a second filter material 134 is
melted, welded or otherwise affixed to the removable cap 116 of the
filtration column 100, i.e., when the cap 116 is inserted in the
second end of the tubular column 114. As such, the first filter
material 132 retains the column matrix material by closing-off the
first opening 124 in the bottom end of the column 114 while the
second filter material 134 retains the column matrix material 112
by closing-off the second end of opening 126 in the tubular column
114.
Upon contact with the fluid sample, the column matrix material 112
is hydrated to fill the width of the tubular column 114.
Furthermore, the column matrix material 112 grows to a prescribed
length necessary to remove the target molecular material from the
fluid sample. As fluid passes through the column matrix material
112, it traps small molecule materials in the matrix while allowing
large molecule materials to pass. In the described embodiment, the
small molecule material is sodium chloride (i.e., salt), however,
the fluid dynamics described herein are applicable to any
filtration material requiring a particular length of matrix
material to remove a select molecule. For example, the column
matrix material 112 may remove materials from a group comprising,
but not limited to: phosphates, sodium and polysaccharides. In the
described embodiment, the large molecule material may be a
deoxyribonucleic acid (DNA) molecule. It is this large molecule
material which will ultimately be deposited in the collection
chamber 36 and screened for testing.
It should be appreciated that the filter material 132, 134 may be
any conventional screening material which allows molecules of a
particular size to pass. In the described embodiment, the filter
materials 132, 134 allow both large and small molecules to pass.
Accordingly, the filter materials 132, 134 do not remove molecules
from the fluid assay sample, but merely function as a convenient
solution to retain the both the dehydrated and hydrated column
matrix material in the tubular column 114. Furthermore, the filter
materials 132, 134 allow the passage of molecules larger than those
trapped by the column matrix material 114.
The cap 116 is configured to be inserted into the second or upper
end 126 of the tubular column 112, functionally retains the other
end of the column matrix material 114, and defines a passageway
configured to direct a filtered fluid sample from the tubular
column 114 into the collection chamber 36. Alternatively, or
additionally, the cap 116 may be configured to restrict the volume
of the filtered fluid sample collected above the column matrix
material 112 and maintain a pressurized flow path.
The cap 116 includes a substantially planar cover 136, an annular
rim 138 projecting orthogonally from the plane of the cover 136,
and a fluid guide 142 also projecting from the cover 136 and
defining a fluid path or passageway 150 from the upper portion of
the column matrix material 112 to the collection chamber 36. The
annular rim 138 of the cap 116 is configured to be inserted into
the upper end, i.e., into the upper opening 126, of the tubular
column 114 and includes an effluent opening 146 (best seen in FIG.
10) aligned with a transverse opening 148 in the wall of the
tubular column 114. More specifically, the fluid guide 142 of the
cap 116 is configured to receive a filtered fluid sample from the
aligned openings 144, 146 to direct the filtered fluid sample into
the collection chamber 36 of the disposable cartridge 20.
In FIG. 11, a schematic of the filtration column 100 is depicted
with the cap 116 inserted in the upper end 126 of the tubular
column 114. As eluded to supra, the cap 116 reduces the volume of
filtered assay fluid which may collect on the top of the column
matrix material 112. As such, the cap 116 retains sufficient head
pressure, and creates a pressurized passageway 150 which avoids the
difficulties associated with the surface tension between the upper
end of the filtration column 100 and a film cover which
encapsulates the various cavities and chambers 30, 32, 34, 36 of
the disposable cartridge 20.
Flow Control System
While the previous section disclosed an embodiment relating to one
chamber for filtration and another for collection of a filtered
assay fluid, the following section relates to improvements
pertaining to flow control between the syringe barrel 22B and the
plurality of ports 16 disposed about the periphery of the rotor 18.
During a period of development, understanding and discovery, the
inventors learned that the manufacture of the disposable cartridge
20, and in particular, the manufacture of the syringe barrel 22B
and the rotor 18, presented certain challenges that could only be
addressed by a novel compliant over-mold 200 disposed between the
rotor 18 and the stationary cartridge body 22. Before discussing
the compliant over-mold 200, it will helpful to understand some
other considerations pertaining to the need for the compliant
over-mold 200.
Various methods for manufacturing the rotor and cartridge body 22
were considered in the early stages of the cartridge development.
It will be appreciated that for the cartridge to be disposable,
(i.e., used only once), it must be extremely inexpensive to
fabricate, i.e., to satisfy the margins necessary for
profitability. On the other hand, both the rotor and cartridge body
are intricate, i.e., requiring a multiplicity of very narrow
apertures 18P and channels 40, 42 (shown in FIGS. 3 and 4). One
manufacturing approach considered by the inventors involved a
combination of molding and machining steps. For example, the rotor
18 and cartridge body 22 may be independently molded, and
subsequently machined to produce the many intricate rotor and
syringes ports 18P, 22P. Furthermore, this approach facilitates the
fabrication of the requisite narrow ports 18P, 22P, which enables
surface tension developed in the ports 18P, 22P to prevent backflow
contamination of the assay fluids. While this approach provides the
desired port dimensions, the subsequent machining operation is far
too costly for a diagnostic system which employs disposable
cartridges 20.
Another approach involved injection molding which significantly
reduces manufacturing costs, however, this method also has certain
limitations relating to the dimension/diameter of the rotor and
syringe ports 18P, 22P. More specifically, the molding pins used to
fabricate the ports 18P, 22P must maintain a certain threshold
dimension to prevent the molding pins from failing or fracturing
during the injection molding process. As such, the requisite pin
size for fabricating the ports 18P, 22P is significantly larger
than the optimum port dimension for preventing backflow
contamination. As such, the port size which must be maintained
cannot take advantage of the properties of surface tension to
prevent backflow contamination. Consequently, a need arose for a
fabrication method which employs injection molding as the principle
fabrication technique (to keep costs to a minimum) while producing
the requisite port size without resorting to more expensive
manufacturing methods.
In FIGS. 12 and 13, disposable cartridge 20 comprises a rotor 18,
cartridge body 22, and a flow control system 200 operative to
prevent cross-contamination of fluid sample reagents from one assay
chamber to another assay chamber. As described supra, the rotor 18
comprises a plurality of assay chambers 30, 34 rotatable about an
axis 18A and rotationally mounted to the cartridge body 22.
Furthermore, the rotor 18 defines a peripheral surface, i.e., a
cylindrical surface 18S, having a plurality of ports 18P disposed
about the surface 18S and extending through the wall 18W which
defines the peripheral surface 18S. The cartridge body 22, on the
other hand, comprises a syringe barrel 22B operative to inject and
withdraw assay fluids in response to axial displacement of a
syringe plunger 28 disposed within the syringe barrel 22B. Both the
rotor 18 and cartridge body 22 includes ports 18P and 22P,
respectively, which are fabricated using a conventional injection
molding process. Accordingly, the port size is limited by the pin
restraints of an injection molding process.
To combat the difficulties associated with cross-contamination of
fluid sample reagents, a moldable, compliant valve, or elastomer
over-mold 200, was interposed between the rotor 18 and cartridge
body 22. In FIGS. 12-16, the elastomer or compliant over-mold 200
defines at least one compliant opening 204 having a maximum opening
dimension which is smaller than the dimension of the rotor ports
18P. Furthermore, the compliant openings 204 has a maximum opening
dimension which is smaller than the dimension of the barrel port
22P. In the described embodiment the average opening dimension of
the barrel port 22P is about 1.3 mm whereas the opening dimension
of the compliant opening is less than about 0.6 mm and preferably
less than about 0.3 mm. Operationally, the compliant opening 204 is
configured to: (i) enlarge when fluid pressure is applied in
response to axial movement of the plunger 28 during injection and
(ii) diminish in size when fluid pressure is reduced.
In one embodiment, depicted in FIGS. 14-16, the compliant opening
204 includes intersecting cuts 212 configured to cross the opening
of the barrel port 22P. In this embodiment, the X-shaped opening
has flexible corner segments 204A, 204B which may flap or bend so
as to produce a larger opening, i.e., to permit a larger flow of
assay fluid through the compliant opening 204. Consequently, the
corner segments 204A, 204B of the compliant opening 204 function as
a valve, i.e., opening to permit a greater flow rate in response to
positive pressurization and closing in the absence of the positive
pressurization. It will also be appreciated that the segments 204A,
204B may flex in the opposite direction to allow fluid to be
withdrawn from an assay chamber 30, 32, 34. Accordingly, the
compliant X-shaped opening can also function as a two-way valve,
i.e., opening in one direction to allow flow in that direction and
in another direction to allow flow in the opposite direction. To
further increase the flow rate across the intersecting cuts 204, a
portion of the cross-over region, i.e., the portion closest or
proximal to the cross-over cuts can be removed or eliminated to
facilitate flow. In the described embodiment, the portion of the
cross-over region 212 which is removed is less than about 0.5 mm
and in another embodiment the region 212 is less than about 0.3
mm.
In another embodiment, depicted in FIGS. 17-19, the compliant
opening 208 may comprise a flap 210 mounted to an edge of the
opening 208 by a flexible elastomer hinge 214. In this embodiment,
the compliant opening 208 includes a frustum-shaped opening 218
while the flap 210 includes an edge which is complimentary-shaped
to seat in the frustum-shaped opening 218. Similar to the previous
embodiment, the compliant opening 208 has a maximum opening
dimension which is smaller than the dimension of the rotor ports
18P. Furthermore, the compliant opening 208 has a maximum opening
dimension which is smaller than the dimension of the barrel port
22P. Both the rotor and barrel ports 18P, 22P are shown in dashed
or phantom lines in FIGS. 17-19.
Operationally, the flap 210 of the compliant opening 208 is
unseated as the pressure within the syringe barrel increases to
inject assay fluid into the rotor 16 through one of the ports 18P.
The increased pressure causes the flap 210 to pivot about the hinge
axis to dispense the assay fluid into an assay chamber 32, 34, 36.
Once this step is completed, the pressure is withdrawn such that
the flap 210 closes and is reseated into the frustum-shaped
opening. Next, the signal processor provides a signal to rotate the
rotor to a new rotational position. The flap 210 of the compliant
opening functions to prevent backflow of the recently deposited
assay fluid into the syringe barrel 22B. As such, the X-shaped
compliant opening 204, and the hinged flap 208 contained in the
elastomer over-mold 200, prevent assay fluids from being wicked or
drawn (should the syringe barrel 22 retain a small negative
pressure or pocket of positive pressure) into the barrel port 22P.
Accordingly, the over-mold valves 204, 208 ensure that the test
results will not be tainted and will be accurate.
In yet another embodiment shown in FIGS. 12 and 13, the ports of
the flow control system may be disposed on different geometric
planes. Alternatively or additionally, ports having compatible
reagents may be in fluid communication with one syringe
barrel/plunger while ports having incompatible reagents may be in
fluid communication with a different syringe barrel/plunder so as
to separate/isolate incompatible reagents from each other. For
example, reagents of one type may be injected by one of the syringe
barrels/plungers 22B-1, 28-1 while reagents of another type may be
injected by another one of the syringe barrels/plungers 22B, 28-2.
In FIG. 13, a backside surface of the elastomer over-mold 200 is
shown depicting two compliant openings 224, 228. One of the
X-shaped compliant openings 224 is disposed proximal the bottom
surface or plane of the rotor 18 and is fed by a first syringe
barrel 22B-1 deployed on one plane of the disposable cartridge 20.
A second X-shaped compliant opening 228 is fed by a second syringe
barrel 22B-1 deployed on a second plane of the disposable cartridge
20. In the described embodiment, the port 224 disposed in one plane
is separated or spaced apart from the port 228 disposed in another
plane by a threshold or prescribed vertical distance.
In another embodiment of the disclosure, at least one of the rotor
ports 18P includes a high viscosity gel disposed in the bore of the
respective port 18P. The high viscosity is injected into at least
one of the rotor ports 18P such that the gel extends the full
length of the port, i.e., on average about 1.5 mm.
Operationally the gel is displaced under pressure to facilitate the
transfer of fluid sample reagents from one assay chamber to
another. In the described embodiment, at least one of the rotor
ports 18P define a fluid volume which is less than about 15
microliters to mitigate back-flow of a fluid sample reagent.
Co-Molded or Dual Material Rotor for Enhanced Thermal and Conformal
Properties
In another embodiment of the disclosure, the rotor 18 comprises
different materials to enhance the thermal and conformal properties
of the disposable cartridge 20 Depending upon material
compatibility, the rotor 18 may be molded in segments and
subsequently joined/welded to form a complete rotor 18. By
fabricating the rotor 18 employing at least two different
materials, e.g., one segment having conductive properties and
another segment fabricated from a high modulus material (having
high strain properties), the rotor 18 can provide enhanced
performance. For example, a lower portion of the rotor 18 can be
fabricated using conductive materials to function as a heat sink.
As such, a heating element (not shown in the drawing) can deliver
heat to various chambers 32, 34, 36 and channels 40, 42 to
accelerate reagent reactions and improve the performance of the
disposable cartridge 20.
The rotor segments can be fabricated using a thermally conductive
plastic or a thermally conductive elastomer. Both materials have
superior thermal properties to standard polypropylene while the
addition of elastomer has added conformal properties. Lastly,
inasmuch as the upper segment of the rotor may comprise a material
having low thermal conductivity, this segment will have insulating
properties to retain heat in regions where it provides the most
benefit.
Enhanced Mixing
One of the requirements of the disposable cartridge 20 is the
admixture of reagent fluids in the various chambers 30, 32, 34, 36
to ensure a complete, thorough and reliable result. While the
diagnostic assay system 10 may include shakers, mixers and
vibration inducing actuators, one of the easiest structures to
accomplish mixing in a chamber includes a spinner, vortex generator
or flow disruptor. FIGS. 20 and 21 depict another embodiment of the
disposable cartridge wherein a vortex generator 300 is disposed
above a port 18P extending through the bottom panel of the rotor
18. As assay fluid is injected into the port 18P, the fluid
immediately encounters a disruptor in the fluid flow. The vortex
generator 300 generates mixing vortices causing the injected fluid
to mix with a fluid, e.g., a lysis buffer, in the chamber 32 of the
rotor 18.
Sumps, Tapered Floors and Rounded Corners
In another embodiment and referring to FIG. 22, the configuration
of the rotor 18 and its chambers 30, 32, 34 and 36 may be
configured to better extract all the contents from a reservoir. As
such, sump areas may be created, corners of the walls may be
rounded and the bottom panel 44 may be pitched or inclined in a
direction toward a port 54 projecting upwardly through the bottom
panel 44 of the rotor 18.
Heated Channels
In another embodiment and referring to FIG. 22, a large channel
region 52 may be located on the bottom 44 of the rotor 18 and
configured to be sufficiently large to retain and entire sample and
lysing buffer mixture. As such, the high volume channel 52 may be
positioned over a heating element (not shown) and integrated with a
film disposed over the bottom channels 40, 42, and 52, to
accelerate the reagent reactions occurring in the mixture.
Isolated Multi-Zoned Multiplexed PCR Using a Single Buffer
In yet another embodiment and referring to FIG. 23, one or more
channels 40, 42 will be constructed in a segmented design in which
PCR primers may be dispensed, dried and stored in individual
segments 400. A subsequent coating may be applied to further
encapsulate the dried primers 410. The coating serves two
functions: (1) to preserve and protect the primers and (2) to
prevent premature rehydration of the primers when the channel 420
is filled with a buffer material. Concerns relating to lateral
diffusion may be minimized by the low primer diffusion rate, spot
to spot distance (e.g., 3 to 5 mm.) and the use of narrow channels
separating the spotted regions (choke point).
In another embodiment depicted in FIG. 24, isolation of the PCR
regions can be achieved by utilizing small wells 500 created in a
bottom film using a laminated film processing technique. The micro
wells 500 would contain the dried primers 510 and other desired
components. Upon filling the micro wells 500, i.e., performed in
step (a) with a common buffer, the micro wells 500 may be filled in
a step (b) to re-suspend the primers 510. A secondary, non-miscible
fluid such as mineral oil may be added in a step (c) to cap the
micro wells 500. With the micro wells sealed, in step (d), with the
mineral oil, the PCR process can be performed. Extraction of the
fluid in step (e) would first involve replacing the mineral oil
with a suitable aqueous buffer. Due the large concentration
gradient, a large quantity of the PCR product would then diffuse
into the buffer.
To prevent the primer 510 from spreading during the loading phase,
an encapsulant may be used. The encapsulant may be water soluble,
semi-water soluble or temperature sensitive in order to prevent
immediate rehydration of the primers. Upon filling, the encapsulant
will slowly dissolve and eventually allow for the primers to be
re-suspended into the buffer. A temperature sensitive encapsulant
would maintain its integrity until a critical temperature is
reached, wherein it is broken down allowing the primers to
re-suspend.
Syringe Isolation and Containment
While previous embodiments involved the prevention of
cross-contamination from chamber to chamber, the possibility for
cross-contamination can occur from one disposable cartridge to
another disposable cartridge. For example, the possibility exists
that the syringe shaft 26, which is part of the portable diagnostic
assay system 10, may be contaminated by a previously used
disposable cartridge 20. That is, the shaft 26 which actuates the
plunger 28 may be contaminated by assay materials in the syringe
barrel 22, i.e., as the shaft wipes against the barrel opening for
receiving the shaft 26.
FIGS. 26a-26e depict various configurations of the syringe barrel
22 for preventing cross-contamination between cartridges 20. During
a normal syringe actuation, the shaft which drives the plunger 28
is exposed to the outside environment (see FIG. 26a). During this
state, it is in theory, possible for trace reagent residue and
particulates to be left exposed due to insufficient plunger
sealing/scraping and thus risking contamination on the syringe
shaft or other areas. In one embodiment, shown in FIG. 26a, a
disposable shaft 600 detachably mates with the plunger 28 at one
end and removeably mounts to a permanent shaft (not shown) within
the portable diagnostic assay system 10. This minimizes the risk of
syringe shaft contamination as it is discarded along with the
cartridge 20.
In another embodiment, illustrated in FIG. 26b, a disposable shaft
600 passed through a series of elastomer flaps/baffles 610 which
function as multiple gaskets. The flexible nature of the elastomer
allows the shaft 600 to operate while maintaining intimate contact
with the shaft reducing the possibility of exposure.
In another embodiment, depicted in FIG. 26c, a disposable shaft 600
is connected to one end of a flexible bellows 620 which, in turn,
mounts at its other end of the syringe barrel 28. As the shaft 600
extends and retract, the bellows 620 expands and collapses This
configuration completely isolates the syringe shaft 600 from the
internal environment of the syringe barrel 28.
In yet another embodiment, shown in FIG. 26d, the disposable shaft
600 connects to a second plunger 630 disposed a threshold distance
X from the primary or working plunger 28. The disposable shaft 600,
working plunger 28 and secondary plunger 630 is inserted into a
syringe barrel 22 which is elongated by the same threshold distance
between the plungers 28, 630. The primary plunger 600 is used as a
traditional plunging mechanism and is responsible for moving the
fluid into the cartridge. The secondary plunger 630 functions as a
containment device and is spaced from the primary plunger 28 such
that secondary or containment plunger 630 never passes into the
working area (or stroke) of the primary plunger 28. This prevents
contaminants from being conveyed to the secondary or containment
plunger 630. A permanent shaft 650 extends beyond the elongated
syringe barrel 22 where it is mated to the linear actuator or
control motor a syringe control motor.
While the invention has been described with reference to particular
embodiments, it will be understood by those skilled in the art that
various changes may be made and equivalents may be substituted for
elements thereof without departing from the scope of the invention.
In addition, many modifications may be made to adapt a particular
situation or material to the teachings of the invention without
departing from the scope of the invention.
Therefore, it is intended that the invention not be limited to the
particular embodiments disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include
all embodiments falling within the scope and spirit of the appended
claims.
* * * * *